Preheat the oven to 200c/400F/Gas 6/Fan 180. Line a baking sheet with baking parchment.

Melt the butter in a saucepan, remove from the heat and stir in the flour to make a roux. Stir or whisk in the milk, a little at a time, then return the pan to a medium heat and cook, whisking constantly, for approximately 5 minutes, until the sauce is thick and smooth.

Remove from the heat and stir in the mustard (if using) along with the gruyere, cheddar and 2 tbsp of the Parmesan. The sauce should be quite thick. Season to taste with pepper and a very little salt (remember that the ham will be quite salty).

Lay the 4 pancakes out on a clean, flat surface and spoon 1/4 of the sauce in a line down the centre of each pancake.

Scatter the ham over the sauce then roll up each pancake to make a “fat cigar” shape. Carefully transfer the filled crepes to the prepared baking sheet, placing them seam side down on the baking sheet.

Scatter the remaining Parmesan carefully over the top of the crepes and bake for 15 minutes, until the crepes are crisp and brown on the edges and base. Transfer to plates using a fish slice and cool slightly before serving.

Method

Preheat the oven to 200c/400F/Gas 6/Fan 180. Line a baking sheet with baking parchment.

Melt the butter in a saucepan, remove from the heat and stir in the flour to make a roux. Stir or whisk in the milk, a little at a time, then return the pan to a medium heat and cook, whisking constantly, for approximately 5 minutes, until the sauce is thick and smooth.

Remove from the heat and stir in the mustard (if using) along with the gruyere, cheddar and 2 tbsp of the Parmesan. The sauce should be quite thick. Season to taste with pepper and a very little salt (remember that the ham will be quite salty).

Lay the 4 pancakes out on a clean, flat surface and spoon 1/4 of the sauce in a line down the centre of each pancake.

Scatter the ham over the sauce then roll up each pancake to make a “fat cigar” shape. Carefully transfer the filled crepes to the prepared baking sheet, placing them seam side down on the baking sheet.

Scatter the remaining Parmesan carefully over the top of the crepes and bake for 15 minutes, until the crepes are crisp and brown on the edges and base. Transfer to plates using a fish slice and cool slightly before serving.